Working The Stock Exhaust Guide and Boss Area

[jack]

Final stage complete and I've posted a few shots of the guide profiling,hopefully you can grasp what I've done.......Later Jack

[ttmaniac]

What kind of power gains can you expect from these mods?

[mashermoto]

Jack, thanks for the additional detail. I'm just a few weeks away form putting your post to practice

Just two easy questions:

The reduced guide and boss look like a must do for maximum performance applications. It really opens up the port. But for a street application where a person seeks additional performance, but also wishes longevity of the engine, could any significant gains be obtained by profiling the boss area around the stock valve guide? I was considering keeping the guide at stock length to help shield heat off the valve stem. I wouldn't mind giving up a little performance in trade.

The second question has to do with the #9 photo. Just where does that sleeve thingy fit

[otto]

MAAAAN Jack,
She's lookin GOOD!
I've been wondering which product you use for the thermal barrier, the c-kote or the ceramic fill? My guess is the c-kote. (Hope that's not a proprietary secret) :-)
I was thinking about ordering some c-kote for the pistons. Applying it to the valves makes sense too. I assume you apply to the whole valve, stem and all for best effect then. I might be showing off my iggerance here, but what about the combustion chamber too, and maybe the exhaust ports?
Thanks for the awesome work Jack! You Da man.

[bill]

Perhaps the best photos and explanations I've seen on porting. Thanks for explaining all this Jack. Bill

[crazypj22]

Jack,
Are those sleeves alloy or steel?
They look like aluminium alloy, any problems with them burning?
PJ

[ttmaniac]

What kinds of gains could be expected? What kind of cam, pipes, and carbs do you run with this head?

[gdjohnson]

Jack,
You do some nice work man!!
Greg

[eric123]

+1

[mashermoto]

Hey Jack...what are the cutting length and cutting diameter of those two rotary files you use?

[crazypj22]

I use single cut burrs (usually used on steel) as they slow down cutting compared to Alumihoggers.
They tend to clog more easily but if you use Crisco or similar as cutting lube its not too bad. (and cheap ;D)
I shorten them from 6" to about 4.5" as it gives better control.
I also buy the 3" long for 'roughing out'.
Favorite are 3/8" rounded tree and 3/8" pointed tree shapes, but I also use 1/4" ball end and tree shapes plus 14.5degree taper cutters with rounded nose.
Couple of different manufacturers, see pic.
PJ

[jack]

I have a variety of cutters that I purchase from Matco Tools for the life time replacement But I prefer the straight cutters to work out the rough casting flaws in the pockets, opening up the cross sectional area of the spigot and pre-shaping the guide bosses but for my final shape I'll go through a few boxes of abrasive rolls. I get the abrasives rolls through Standard Abrasives cuz they'll custom make the grit I prefer or get'em through Merit. I usually just dip the cutter tips in transmission fluid to prevent clogging up and hit the trigger to spin off the excess fluid.The cutters are 6 inches in length with 1/4 and 3/8 heads.............Jack

[hulkamaniac]

This is an awesome thread with great pics, I wish I had that good a camera.

And the skill too!!!!

[2003viper]

Jack,do you do porting for others? If so what does it cost?(ball park)

[jack]

For all you DIY who wish to port your heads all linked images will lost sometime at the end of February or the beginning or March. I simply don't use Photo Buckets anymore or any site to host my pictures and have no back up system for the images. I signed one more time on PBs to keep the images up for ninety days,after that they will be lost,just giving you a heads up to start coping this information.

Just to add a extra note to this thread, on the roof and guide boss, remove little as possible in the roof and ROUND profile the guide boss,depending what's available in the floor will depend how the roof gets worked and turned,you're better off just keeping it simple to avoid the mistake of removing to much and slowing down port velocity.